Project: T173700 #3724

This R&D assignment will review the hazards from existing construction procedures and explore awide-range of barriers and mitigation methods to reduce the step and touch potentials. Theproposed project will address various issues and their solutions that can be used by the membersto review their practices and improve or change where necessary.

This project will provide an analytical review of the step and touch potentials resulting duringvarious construction and maintenance activities of substation expansion. The study objectivesinclude:


  1. Review the hazard resulting from existing construction procedures
  2. Explore a wide range of barriers and procedures to reduce step and touch potentials
  3. Quantify the efficiency and hazard reduction offered by differing mitigation methods


The proposed study will address the following issues (among others resulting from solutions thatremain to be developed):

  • The efficiency of gradient control mats on different soils and weather conditions
  • The isolation provided by rubber mats when wet and soiled
  • The practicality of placing mats over large areas
  • How work sites can accommodate both mats and wheeled vehicles
  • Specifications for isolation transformers used to supply tools
  • Certain tools (such as crimping presses for connectors) may already have adequatehydraulic isolation
  • The effectiveness of isolating a new ground grid from the existing station given theirgalvanic coupling through soil
  • Procedures that require the use of gloves
  • Procedures that benefit from temporary bonds between metallic objects
  • When metallic fences around the work site can transfer hazardous potentials
  • Changes to the sequence of work procedures that reduce accidental potentials